GNSS ARAIM保护水平计算方法及性能分析

Performance analysis of GNSS ARAIM protection level calculation methods

针对全球卫星导航系统(GNSS)中高级接收机自主完好性监测(ARAIM)技术采用不同的计算保护水平(PL)的方法,这些不同方法计算得到的PL之间的差异和对用户可用性的影响不明的问题,提出一种GNSSARAIM保护水平算法的性能分析方法:介绍4种PL计算方法,并分析它们之间的数理关系;然后基于多模GNSS实验跟踪网(MGEX)跟踪站多天的全球定位系统(GPS)和北斗卫星导航系统(BDS)实测数据以及城市车载动态数据,比较分析4种方法计算得到的PL数值和计算时间上的差异;最后利用仿真模拟计算分析4种方法对全球用户可用性和覆盖率的影响。结果表明,基于分隔解(SS)检验量且完好性风险优化分配的PL方法在运行时间上与其他3种方法的差异最大不超过0.2s,该方法在实测数据实验中计算得到的PL最小,具有最优性能;在仿真实验中全球范围内VPL值(99.9%)小于35m的覆盖率在4种方法中最高,可达81.32%;此外,双系统下4种方法全球用户的覆盖率均为100%,均可满足垂直引导至200英尺高度定位器性能(LPV-200)阶段的可用性指标。

Aiming at the problem that the technology of advanced receiver autonomous integrity monitoring(ARAIM)in global navigation satellite system(GNSS)use different methods to calculate protection level(PL),and the differences between the PLs calculated by these different methods and the impact on user availability are unknown,the paper proposed a performance analysis method of GNSS ARAIM protection level algorithms:four PL algorithms were introduced,and the mathematical relations between them were analyzed;then,based on the measured data of global positioning system(GPS)and BeiDou navigation satellite system(BDS)of the multi-GNSS experiment(MGEX)tracking stations for several days and the dynamic data of the city vehicles,the differences of PL values and calculation time obtained by the four methods were comparatively analyzed;finally,the impact of the four methods on global user availability and coverage was analyzed by simulation calculation.Results showed that the PL method based on the solution separation(SS)test statistics and the integrity risk optimization allocation would have a maximum difference of 0.2 s from the other three methods in running time,and in the test of measured data,the minimum PL and optimal performance could be achieved by this calculation method;moreover,in the simulation experiment,the global coverage of VPL values(99.9%)less than 35 m of this method would be the highest among the four methods,reaching 81.32%;in addition,the global user coverage of the four methods under dual-system would be 100%,which could meet the availability requirement of localizer performance with vertical guidance-200 feet(LPV-200)approaches.